Semiconductor device

ABSTRACT

Provided is a semiconductor device, in which: patterns for detecting displacement at probing are formed of a plurality of minute conductors formed below a protective film; each of the plurality of minute conductors formed below the protective film is electrically insulated and formed to be smaller than a bottom surface of a tip of a probing needle used for carrying out an electrical measurement of IC chips; and the patterns for detecting displacement at probing are provided in a pair for each of the IC chips.

This application claims priority under 35 U.S.C. §119 to Japanese PatentApplication No. JP2006-166879 filed Jun. 16, 2006, the entire content ofwhich is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to detection patterns for detectingdisplacement of a probe at the time of probing in a semiconductor devicehaving a plurality of IC chips formed of elements such as a transistorand a pad for probing formed on a silicon substrate.

2. Description of the Related Art

Conventionally, a probing test is generally carried out on an ordinaryIC for checking electrical characteristics of a complete product.

Further, minimizing intervals between pads used in a probing testenables chip size reduction in an IC having many pads, and isindispensable to reduce IC cost.

In the probing test, which is often carried out with a thin detectionneedle, effect of displacement of the needle is larger in an IC havingmany pads for probing since the pad interval is small. Not onlyhorizontal displacement of the needle in probing but also aninappropriate state of the needle in a depth direction (position ordepth of entry of the needle) may prevent acquisition of correctelectrical characteristics. Accordingly, in the probing test, detectionof the displacement of the probing needle at the testing site isdesirable in order to determine whether the test is carried outappropriately or not. A Japanese patent application JP 6-45419 A, forexample, discloses a technique in which pads for detecting displacementof a needle at a time of probing is provided to carry out a measurement.

As described in the above, however, effect of displacement of the needleis larger in an IC having many pads for probing since the pad intervalis small, resulting in the problems of inaccurate probing test, andcapture of erroneous characteristics, and the like. In order to solvethese problems, for example, a technique has been disclosed where aplurality of special pads for detecting displacement of a needle inoperation are provided while carrying out measurement. However, suchtechnique has problems of the large occupation area for pads, inabilityin detecting the direction of the displacement, inability in acquiringinformation along the depth direction, and the like.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problems, according to an aspectof the present invention, a semiconductor device is structured asfollows.

That is, there is provided a semiconductor device in which patterns fordetecting displacement at probing are formed of a plurality of minuteconductors formed below a protective film. Further, in the semiconductordevice, each of the plurality of minute conductors formed below theprotective film is electrically insulated and formed to be smaller thana bottom surface of a tip of a probing needle used for carrying out anelectrical measurement of the IC chips. In addition, in thesemiconductor device, the patterns for detecting displacement at probingare provided in a pair for each of the IC chips.

With the construction described above, a semiconductor device havingpatterns for detecting displacement at probing which occupy a smallarea, which can detect not only an amount of transverse displacement butalso a direction of the displacement, and which can obtain informationin a depth direction can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a schematic sectional view illustrating a moment in whichappropriate probing is carried out in a first embodiment of patterns fordetecting displacement at probing according to the present invention;

FIG. 2 is a schematic sectional view illustrating a moment in which aprobe is transversely displaced in the first embodiment of the patternsfor detecting displacement at probing according to the presentinvention;

FIG. 3 is a schematic sectional view illustrating a moment in which anamount of overdrive (pushdown) to the probe is insufficient in the firstembodiment of the patterns for detecting displacement at probingaccording to the present invention;

FIG. 4 is a schematic diagram illustrating capacitance between dotpatterns 601 to 605 for detecting capacitance and a probe needle 801 inthe state illustrated in FIG. 1;

FIG. 5 is a schematic diagram illustrating the capacitance between thedot patterns 601 to 605 for detecting capacitance and the probe needle801 in the state illustrated in FIG. 2;

FIG. 6 is a schematic diagram illustrating the capacitance between thedot patterns 601 to 605 for detecting capacitance and the probe needle801 in the state illustrated in FIG. 3;

FIG. 7 is a schematic plan view illustrating an arrangement of patternsfor detecting displacement at probing in a second embodiment of thepresent invention; and

FIG. 8 is a schematic plan view illustrating an arrangement of patternsfor detecting displacement at probing in a third embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a schematic sectional view of the first embodiment of asemiconductor device according to the present invention showing aninstant when an appropriate probing is carried out by using detectingpatterns for displacement at probing.

Dot patterns 601 to 605 for detecting capacitance, which are made ofminute conductors such as aluminum, are formed on an underlyinginsulating film 610 made of a silicon oxide film or the like. Therespective dot patterns 601 to 605 are electrically insulated and areindependent of each other. A protective film 701 formed of an insulatingfilm such as a silicon nitride film is formed on the dot patterns 601 to605.

For the sake of simplicity, FIG. 1 shows a partial sectional viewillustrating only five dot patterns of the plurality of dot patterns fordetecting capacitance which are two-dimensionally arranged.

When a probing is carried out for an electrical measurement to the ICchip, the patterns for detecting displacement at probing according tothe present invention are simultaneously probed with needles asillustrated in FIG. 1.

A probe needle 801 is in contact with the protective film 701. The probeneedle 801 is overdriven into (forced into) the protective film 701 in adepth direction to an appropriate extent for carrying out an electricalmeasurement of the IC chip.

The dot patterns 601 to 605 for detecting capacitance and the probeneedle 801 form capacitors through the protective film 701. Thecapacitance values of the dot patterns 601 to 605 for detectingcapacitance vary depending on their distance from the probe needle 801.In order to precisely detect a change in the capacitance, each of thedot patterns 601 to 605 for detecting capacitance is formed to besmaller than a bottom surface of the probe needle 801.

FIG. 4 is a schematic diagram illustrating the capacitance between thedot patterns 601 to 605 for detecting capacitance and the probe needle801 in the state illustrated in FIG. 1.

As illustrated in FIG. 4, the capacitance values have a maximum at thedot pattern 603 positioned at the center and decrease on both sides asthey go further. Measurement of the capacitance for appropriate probingin advance permits the setting of a capacitance clearance line 901.

In the example illustrated in FIG. 4, the capacitance values graduallydecrease toward the dot pattern 601 for detecting capacitance and towardthe dot pattern 605 for detecting capacitance with the dot pattern 603being the center.

The capacitance values of the dot patterns 602, 603, and 604 fordetecting capacitance are above the predetermined clearance line 901.

As described above, in FIG. 4, the shape taken by the capacitancevalues, which gradually decrease toward the dot pattern 601 fordetecting capacitance and toward the dot pattern 605 for detectingcapacitance with the dot pattern 603 being the center, shows that notransverse displacement of the needle is detected. Further, it can beunderstood that the probing in the depth direction is also appropriatebecause the capacitance values of the dot patterns 602, 603, and 604 fordetecting capacitance are above the predetermined clearance line 901. Inthis way, characteristics which reflect the appropriate probing asillustrated in FIG. 1 can be detected.

FIG. 2 is a schematic sectional view illustrating a probing in which theprobe is transversely displaced in the first embodiment of thesemiconductor device according to the present invention.

The dot patterns 601 to 605 for detecting capacitance, which are formedof minute conductors, are formed on the underlying insulating film 610.The respective dot patterns 601 to 605 for detecting capacitance areelectrically insulated and are in isolation from each other. Theprotective film 701 is formed on the dot patterns 601 to 605.

For the sake of simplicity, FIG. 2 shows a partial sectional viewillustrating only five dot patterns of the plurality of dot patterns fordetecting capacitance which are two-dimensionally arranged.

When a probing is carried out for an electrical measurement to the ICchip, the patterns for detecting displacement at probing according tothe present invention are simultaneously probed with needles asillustrated in FIG. 2.

The probe needle 801 is in contact with the protective film 701. Theprobe needle 801 is overdriven into (forced into) the protective film701 in the depth direction to an appropriate extent for carrying out anelectrical measurement of the IC chip.

The dot patterns 601 to 605 for detecting capacitance and the probeneedle 801 form capacitors through the protective film 701. Thecapacitance values of the dot patterns 601 to 605 for detectingcapacitance vary depending on their distance from the probe needle 801.In order to precisely detect a change in the capacitance, each of thedot patterns 601 to 605 for detecting capacitance is formed to besmaller than the bottom surface of the probe needle 801.

FIG. 2 illustrates a moment in which the probe needle 801 istransversely displaced toward the dot pattern 601 for detectingcapacitance.

FIG. 5 is a schematic diagram illustrating the capacitance between thedot patterns 601 to 605 for detecting capacitance and the probe needle801 at the moment illustrated in FIG. 2.

In the example illustrated in FIG. 5, the capacitance values graduallydecrease from the dot pattern 601 for detecting capacitance, which ispositioned at the end of the patterns for detecting displacement, towardthe dot pattern 605 for detecting capacitance. It is to be noted thatthe capacitance values of the dot patterns 601 and 602 for detectingcapacitance are above the predetermined clear line 901.

Consequently, it can be detected that even though the needle istransversely displaced, the probing in the depth direction isappropriate. In this way, characteristics which reflect the state ofprobing in which the probe needle 801 is transversely displaced asillustrated in FIG. 2 can be detected. Other descriptions than that madeabove are similar to that made with reference to FIG. 1, and thus, nofurther description is made here.

FIG. 3 is a schematic sectional view illustrating a state where theamount of overdrive (pushdown) of the probe is insufficient in the firstembodiment of the semiconductor device according to the presentinvention.

The dot patterns 601 to 605 for detecting capacitance, which are formedof minute conductors, are formed on the underlying insulating film 610.The respective dot patterns 601 to 605 for detecting capacitance areelectrically insulated and are in isolation from each other. Theprotective film 701 is formed on the dot patterns 601 to 605 fordetecting capacitance.

For the sake of simplicity, FIG. 3 shows a partial sectional viewillustrating only five dot patterns of the plurality of dot patterns fordetecting capacitance which are two-dimensionally arranged.

When a probing is carried out for an electrical measurement to the ICchip, the patterns for detecting displacement at probing according tothe present invention are simultaneously probed with needles asillustrated in FIG. 3.

The probe needle 801 is in contact with the protective film 701. Theprobe needle 801 is overdriven into (forced into) the protective film701 in the depth direction in order to carry out an electricalmeasurement of the IC chip.

The dot patterns 601 to 605 for detecting capacitance and the probeneedle 801 form capacitors through the protective film 701. Thecapacitance values of the dot patterns 601 to 605 for detectingcapacitance vary depending on their distance from the probe needle 801.In order to precisely detect a change in the capacitance, the dotpatterns 601 to 605 for detecting capacitance are formed to be smallerthan the bottom surface of the probe needle 801.

FIG. 3 illustrates a moment in which, as compared with the examples ofFIGS. 1 and 2, the amount of overdrive of the probe needle 801 isinsufficient compared with the appropriate amount but the probe needle801 is not transversely displaced.

FIG. 6 is a schematic diagram illustrating the capacitance between thedot patterns 601 to 605 for detecting capacitance and the probe needle801 at the moment illustrated in FIG. 3.

In the example FIG. 6, the capacitance values decrease toward the dotpattern 601 for detecting capacitance and toward the dot pattern 605 fordetecting capacitance with the dot pattern 603 which is positioned atthe center of the pattern being the center. However, the capacitancevalue of the dot pattern 603 for detecting capacitance of the maximumvalue is below the predetermined clearance line 901. Accordingly, it canbe detected that, even though the needle is not transversely displaced,the amount of overdrive in the depth direction is insufficient.

In this way, characteristics which reflect the state of probing in whichthe amount of overdrive of the probe needle 801 is insufficient comparedwith the appropriate amount as illustrated in FIG. 3 can be detected.Other descriptions than that made above are similar to that made withreference to FIG. 1, and thus, no further description is made here.

FIG. 7 is a schematic plan view illustrating a second embodiment of thesemiconductor device according to the present invention. Illustrated isan embodiment of an arrangement of the patterns for detectingdisplacement at probing.

A plurality of IC chips 101 having a plurality of pad regions 201 and ascribe region 301, which is a margin used in cutting an IC, providedbetween the plurality of IC chips 101 are formed. Patterns 401 fordetecting displacement at probing are formed in the scribe region 301.

In the example of FIG. 7, the patterns 401 for detecting displacement atprobing are provided in a pair distant from each other for each IC chip101.

The patterns 401 for detecting displacement at probing are formed in apair for the purpose of detecting displacement in a theta direction(displacement in a rotational direction of a semiconductor wafer) at thetime of probing. In order to improve sensitivity, it is preferable thatthe pair of patterns 401 for detecting displacement at probing bearranged to be distant from each other as much as possible. Although, inthe example of FIG. 7, the patterns 401 for detecting displacement atprobing are arranged in a pair for each IC chip 101, when a large numberof IC chips 101 are simultaneously probed, by providing the patterns 401for detecting displacement at probing in a pair for the whole pluralityof IC chips 101 to be simultaneously probed, the area occupied by thepatterns 401 for detecting displacement at probing can be furtherreduced, which is preferable.

FIG. 8 is a schematic plan view illustrating a third embodiment of thesemiconductor device according to the present invention. Illustrated isanother embodiment of the arrangement of the patterns for detectingdisplacement at probing.

The third embodiment differs from the embodiment illustrated in FIG. 7in that, while the embodiment illustrated in FIG. 7 has the patterns 401for detecting displacement at probing in the scribe region 301, thepatterns 401 for detecting displacement at probing are arranged in theIC chip 101.

For the sake of preventing the increase in the area of the IC chips 101due to the area occupied by the patterns 401 for detecting displacementat probing, it is preferable to form the patterns 401 in the scriberegion 301 as illustrated in FIG. 7. The patterns 401 may, however, beformed in the IC chips 101 when there is a margin both in the area ofthe IC chips 101 and in the manufacturing cost. Other descriptions thanthat made above are similar to that made with reference to FIG. 7, andthus, like numerals are used to designate like or identical membersillustrated in FIG. 7 and description thereof is omitted.

1. A semiconductor device, comprising: a silicon substrate; and aplurality of IC chips each including a transistor and a pad region forprobing, and disposed on the silicon substrate; a scribe region adjacentto the plurality of IC chips; and patterns for detecting displacement atprobing provided in one of the scribe region and an interior of theplurality of IC chips, the patterns for detecting displacement atprobing comprising a plurality of minute conductors disposed under aprotective film.
 2. A semiconductor device according to claim 1, whereineach of the plurality of minute conductors disposed under the protectivefilm is electrically insulated and is smaller than a bottom surface of atip of a probing needle used to carry out an electrical measurement ofthe plurality of IC chips.
 3. A semiconductor device according to claim1, wherein the patterns for detecting displacement at probing areprovided in a pair for each of the plurality of IC chips.
 4. Asemiconductor device according to claim 1, wherein the patterns fordetecting displacement at probing are provided in a pair for a group ofIC chips of the plurality of IC chips to be simultaneously measured in aprobing process.